This invention relates to electromagnetic projectile launchers and more particularly to electromagnetic launchers which utilize an alternator as a source of high current to launch one or more projectiles wherein the projectile muzzle velocity can be controlled by controlling the phase angle at which current is switched from the alternator to a pair of projectile launching rails.
Electromagnetic projectile launchers are known which comprise: a pair of generally parallel conductive projectile launching rails; a source of high current; means for switching current from the high current source to the projectile launching rails; and a sliding conductive armature between the rails. Current flow through the rails and armature places an electromagnetic force on the armature which is used to propel the armature and a projectile along the rails. Launchers have been constructed with a high current source which included the series connection of a direct current homopolar generator and an inductive energy storage coil. To launch a projectile, the inductor is initially charged to a predetermined current level through a switch which acts as a short across the projectile launching rails. Then the switch is opened to allow the inductor to discharge through the rails and armature, thereby launching the projectile. These launchers require massive switching systems and additional components to suppress an arc which occurs as the projectile leaves the launching rails. If multishot operation is desired, current switch-off requirements at the muzzle become excessive.
An A.C. generator, or alternator, is an attractive alternative power source for rapid firing electromagnetic launchers since an alternator is self-commutating. By appropriately timing the switching of current to the launcher rails, the alternator can provide the electromotive force necessary to bring current to zero as the projectile leaves the barrel, thereby greatly reducing the required arc suppression circuitry and simplifying the switching system. Current pulses which are used to launch projectiles may be provided every cycle, or every several cycles, depending on the desired pulse rate.